1 /* 2 * Copyright (C) 2004 Intel Corporation <naveen.b.s@intel.com> 3 * 4 * All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or (at 9 * your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 14 * NON INFRINGEMENT. See the GNU General Public License for more 15 * details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 20 * 21 * 22 * ACPI based HotPlug driver that supports Memory Hotplug 23 * This driver fields notifications from firmare for memory add 24 * and remove operations and alerts the VM of the affected memory 25 * ranges. 26 */ 27 28 #include <linux/kernel.h> 29 #include <linux/module.h> 30 #include <linux/init.h> 31 #include <linux/types.h> 32 #include <linux/memory_hotplug.h> 33 #include <acpi/acpi_drivers.h> 34 35 #define ACPI_MEMORY_DEVICE_COMPONENT 0x08000000UL 36 #define ACPI_MEMORY_DEVICE_CLASS "memory" 37 #define ACPI_MEMORY_DEVICE_HID "PNP0C80" 38 #define ACPI_MEMORY_DEVICE_NAME "Hotplug Mem Device" 39 40 #define _COMPONENT ACPI_MEMORY_DEVICE_COMPONENT 41 42 ACPI_MODULE_NAME("acpi_memhotplug"); 43 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>"); 44 MODULE_DESCRIPTION("Hotplug Mem Driver"); 45 MODULE_LICENSE("GPL"); 46 47 /* Memory Device States */ 48 #define MEMORY_INVALID_STATE 0 49 #define MEMORY_POWER_ON_STATE 1 50 #define MEMORY_POWER_OFF_STATE 2 51 52 static int acpi_memory_device_add(struct acpi_device *device); 53 static int acpi_memory_device_remove(struct acpi_device *device, int type); 54 static int acpi_memory_device_start(struct acpi_device *device); 55 56 static const struct acpi_device_id memory_device_ids[] = { 57 {ACPI_MEMORY_DEVICE_HID, 0}, 58 {"", 0}, 59 }; 60 MODULE_DEVICE_TABLE(acpi, memory_device_ids); 61 62 static struct acpi_driver acpi_memory_device_driver = { 63 .name = "acpi_memhotplug", 64 .class = ACPI_MEMORY_DEVICE_CLASS, 65 .ids = memory_device_ids, 66 .ops = { 67 .add = acpi_memory_device_add, 68 .remove = acpi_memory_device_remove, 69 .start = acpi_memory_device_start, 70 }, 71 }; 72 73 struct acpi_memory_info { 74 struct list_head list; 75 u64 start_addr; /* Memory Range start physical addr */ 76 u64 length; /* Memory Range length */ 77 unsigned short caching; /* memory cache attribute */ 78 unsigned short write_protect; /* memory read/write attribute */ 79 unsigned int enabled:1; 80 }; 81 82 struct acpi_memory_device { 83 struct acpi_device * device; 84 unsigned int state; /* State of the memory device */ 85 struct list_head res_list; 86 }; 87 88 static int acpi_hotmem_initialized; 89 90 static acpi_status 91 acpi_memory_get_resource(struct acpi_resource *resource, void *context) 92 { 93 struct acpi_memory_device *mem_device = context; 94 struct acpi_resource_address64 address64; 95 struct acpi_memory_info *info, *new; 96 acpi_status status; 97 98 status = acpi_resource_to_address64(resource, &address64); 99 if (ACPI_FAILURE(status) || 100 (address64.resource_type != ACPI_MEMORY_RANGE)) 101 return AE_OK; 102 103 list_for_each_entry(info, &mem_device->res_list, list) { 104 /* Can we combine the resource range information? */ 105 if ((info->caching == address64.info.mem.caching) && 106 (info->write_protect == address64.info.mem.write_protect) && 107 (info->start_addr + info->length == address64.minimum)) { 108 info->length += address64.address_length; 109 return AE_OK; 110 } 111 } 112 113 new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL); 114 if (!new) 115 return AE_ERROR; 116 117 INIT_LIST_HEAD(&new->list); 118 new->caching = address64.info.mem.caching; 119 new->write_protect = address64.info.mem.write_protect; 120 new->start_addr = address64.minimum; 121 new->length = address64.address_length; 122 list_add_tail(&new->list, &mem_device->res_list); 123 124 return AE_OK; 125 } 126 127 static int 128 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device) 129 { 130 acpi_status status; 131 struct acpi_memory_info *info, *n; 132 133 134 if (!list_empty(&mem_device->res_list)) 135 return 0; 136 137 status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS, 138 acpi_memory_get_resource, mem_device); 139 if (ACPI_FAILURE(status)) { 140 list_for_each_entry_safe(info, n, &mem_device->res_list, list) 141 kfree(info); 142 INIT_LIST_HEAD(&mem_device->res_list); 143 return -EINVAL; 144 } 145 146 return 0; 147 } 148 149 static int 150 acpi_memory_get_device(acpi_handle handle, 151 struct acpi_memory_device **mem_device) 152 { 153 acpi_status status; 154 acpi_handle phandle; 155 struct acpi_device *device = NULL; 156 struct acpi_device *pdevice = NULL; 157 158 159 if (!acpi_bus_get_device(handle, &device) && device) 160 goto end; 161 162 status = acpi_get_parent(handle, &phandle); 163 if (ACPI_FAILURE(status)) { 164 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent")); 165 return -EINVAL; 166 } 167 168 /* Get the parent device */ 169 status = acpi_bus_get_device(phandle, &pdevice); 170 if (ACPI_FAILURE(status)) { 171 ACPI_EXCEPTION((AE_INFO, status, "Cannot get acpi bus device")); 172 return -EINVAL; 173 } 174 175 /* 176 * Now add the notified device. This creates the acpi_device 177 * and invokes .add function 178 */ 179 status = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE); 180 if (ACPI_FAILURE(status)) { 181 ACPI_EXCEPTION((AE_INFO, status, "Cannot add acpi bus")); 182 return -EINVAL; 183 } 184 185 end: 186 *mem_device = acpi_driver_data(device); 187 if (!(*mem_device)) { 188 printk(KERN_ERR "\n driver data not found"); 189 return -ENODEV; 190 } 191 192 return 0; 193 } 194 195 static int acpi_memory_check_device(struct acpi_memory_device *mem_device) 196 { 197 unsigned long current_status; 198 199 200 /* Get device present/absent information from the _STA */ 201 if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA", 202 NULL, ¤t_status))) 203 return -ENODEV; 204 /* 205 * Check for device status. Device should be 206 * present/enabled/functioning. 207 */ 208 if (!((current_status & ACPI_STA_DEVICE_PRESENT) 209 && (current_status & ACPI_STA_DEVICE_ENABLED) 210 && (current_status & ACPI_STA_DEVICE_FUNCTIONING))) 211 return -ENODEV; 212 213 return 0; 214 } 215 216 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device) 217 { 218 int result, num_enabled = 0; 219 struct acpi_memory_info *info; 220 int node; 221 222 223 /* Get the range from the _CRS */ 224 result = acpi_memory_get_device_resources(mem_device); 225 if (result) { 226 printk(KERN_ERR PREFIX "get_device_resources failed\n"); 227 mem_device->state = MEMORY_INVALID_STATE; 228 return result; 229 } 230 231 node = acpi_get_node(mem_device->device->handle); 232 /* 233 * Tell the VM there is more memory here... 234 * Note: Assume that this function returns zero on success 235 * We don't have memory-hot-add rollback function,now. 236 * (i.e. memory-hot-remove function) 237 */ 238 list_for_each_entry(info, &mem_device->res_list, list) { 239 if (info->enabled) { /* just sanity check...*/ 240 num_enabled++; 241 continue; 242 } 243 244 if (node < 0) 245 node = memory_add_physaddr_to_nid(info->start_addr); 246 247 result = add_memory(node, info->start_addr, info->length); 248 if (result) 249 continue; 250 info->enabled = 1; 251 num_enabled++; 252 } 253 if (!num_enabled) { 254 printk(KERN_ERR PREFIX "add_memory failed\n"); 255 mem_device->state = MEMORY_INVALID_STATE; 256 return -EINVAL; 257 } 258 259 return result; 260 } 261 262 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device) 263 { 264 acpi_status status; 265 struct acpi_object_list arg_list; 266 union acpi_object arg; 267 unsigned long current_status; 268 269 270 /* Issue the _EJ0 command */ 271 arg_list.count = 1; 272 arg_list.pointer = &arg; 273 arg.type = ACPI_TYPE_INTEGER; 274 arg.integer.value = 1; 275 status = acpi_evaluate_object(mem_device->device->handle, 276 "_EJ0", &arg_list, NULL); 277 /* Return on _EJ0 failure */ 278 if (ACPI_FAILURE(status)) { 279 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed")); 280 return -ENODEV; 281 } 282 283 /* Evalute _STA to check if the device is disabled */ 284 status = acpi_evaluate_integer(mem_device->device->handle, "_STA", 285 NULL, ¤t_status); 286 if (ACPI_FAILURE(status)) 287 return -ENODEV; 288 289 /* Check for device status. Device should be disabled */ 290 if (current_status & ACPI_STA_DEVICE_ENABLED) 291 return -EINVAL; 292 293 return 0; 294 } 295 296 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device) 297 { 298 int result; 299 struct acpi_memory_info *info, *n; 300 301 302 /* 303 * Ask the VM to offline this memory range. 304 * Note: Assume that this function returns zero on success 305 */ 306 list_for_each_entry_safe(info, n, &mem_device->res_list, list) { 307 if (info->enabled) { 308 result = remove_memory(info->start_addr, info->length); 309 if (result) 310 return result; 311 } 312 kfree(info); 313 } 314 315 /* Power-off and eject the device */ 316 result = acpi_memory_powerdown_device(mem_device); 317 if (result) { 318 /* Set the status of the device to invalid */ 319 mem_device->state = MEMORY_INVALID_STATE; 320 return result; 321 } 322 323 mem_device->state = MEMORY_POWER_OFF_STATE; 324 return result; 325 } 326 327 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data) 328 { 329 struct acpi_memory_device *mem_device; 330 struct acpi_device *device; 331 332 333 switch (event) { 334 case ACPI_NOTIFY_BUS_CHECK: 335 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 336 "\nReceived BUS CHECK notification for device\n")); 337 /* Fall Through */ 338 case ACPI_NOTIFY_DEVICE_CHECK: 339 if (event == ACPI_NOTIFY_DEVICE_CHECK) 340 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 341 "\nReceived DEVICE CHECK notification for device\n")); 342 if (acpi_memory_get_device(handle, &mem_device)) { 343 printk(KERN_ERR PREFIX "Cannot find driver data\n"); 344 return; 345 } 346 347 if (!acpi_memory_check_device(mem_device)) { 348 if (acpi_memory_enable_device(mem_device)) 349 printk(KERN_ERR PREFIX 350 "Cannot enable memory device\n"); 351 } 352 break; 353 case ACPI_NOTIFY_EJECT_REQUEST: 354 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 355 "\nReceived EJECT REQUEST notification for device\n")); 356 357 if (acpi_bus_get_device(handle, &device)) { 358 printk(KERN_ERR PREFIX "Device doesn't exist\n"); 359 break; 360 } 361 mem_device = acpi_driver_data(device); 362 if (!mem_device) { 363 printk(KERN_ERR PREFIX "Driver Data is NULL\n"); 364 break; 365 } 366 367 /* 368 * Currently disabling memory device from kernel mode 369 * TBD: Can also be disabled from user mode scripts 370 * TBD: Can also be disabled by Callback registration 371 * with generic sysfs driver 372 */ 373 if (acpi_memory_disable_device(mem_device)) 374 printk(KERN_ERR PREFIX 375 "Disable memory device\n"); 376 /* 377 * TBD: Invoke acpi_bus_remove to cleanup data structures 378 */ 379 break; 380 default: 381 ACPI_DEBUG_PRINT((ACPI_DB_INFO, 382 "Unsupported event [0x%x]\n", event)); 383 break; 384 } 385 386 return; 387 } 388 389 static int acpi_memory_device_add(struct acpi_device *device) 390 { 391 int result; 392 struct acpi_memory_device *mem_device = NULL; 393 394 395 if (!device) 396 return -EINVAL; 397 398 mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL); 399 if (!mem_device) 400 return -ENOMEM; 401 402 INIT_LIST_HEAD(&mem_device->res_list); 403 mem_device->device = device; 404 sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME); 405 sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS); 406 acpi_driver_data(device) = mem_device; 407 408 /* Get the range from the _CRS */ 409 result = acpi_memory_get_device_resources(mem_device); 410 if (result) { 411 kfree(mem_device); 412 return result; 413 } 414 415 /* Set the device state */ 416 mem_device->state = MEMORY_POWER_ON_STATE; 417 418 printk(KERN_DEBUG "%s \n", acpi_device_name(device)); 419 420 return result; 421 } 422 423 static int acpi_memory_device_remove(struct acpi_device *device, int type) 424 { 425 struct acpi_memory_device *mem_device = NULL; 426 427 428 if (!device || !acpi_driver_data(device)) 429 return -EINVAL; 430 431 mem_device = acpi_driver_data(device); 432 kfree(mem_device); 433 434 return 0; 435 } 436 437 static int acpi_memory_device_start (struct acpi_device *device) 438 { 439 struct acpi_memory_device *mem_device; 440 int result = 0; 441 442 /* 443 * Early boot code has recognized memory area by EFI/E820. 444 * If DSDT shows these memory devices on boot, hotplug is not necessary 445 * for them. So, it just returns until completion of this driver's 446 * start up. 447 */ 448 if (!acpi_hotmem_initialized) 449 return 0; 450 451 mem_device = acpi_driver_data(device); 452 453 if (!acpi_memory_check_device(mem_device)) { 454 /* call add_memory func */ 455 result = acpi_memory_enable_device(mem_device); 456 if (result) 457 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 458 "Error in acpi_memory_enable_device\n")); 459 } 460 return result; 461 } 462 463 /* 464 * Helper function to check for memory device 465 */ 466 static acpi_status is_memory_device(acpi_handle handle) 467 { 468 char *hardware_id; 469 acpi_status status; 470 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; 471 struct acpi_device_info *info; 472 473 474 status = acpi_get_object_info(handle, &buffer); 475 if (ACPI_FAILURE(status)) 476 return status; 477 478 info = buffer.pointer; 479 if (!(info->valid & ACPI_VALID_HID)) { 480 kfree(buffer.pointer); 481 return AE_ERROR; 482 } 483 484 hardware_id = info->hardware_id.value; 485 if ((hardware_id == NULL) || 486 (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID))) 487 status = AE_ERROR; 488 489 kfree(buffer.pointer); 490 return status; 491 } 492 493 static acpi_status 494 acpi_memory_register_notify_handler(acpi_handle handle, 495 u32 level, void *ctxt, void **retv) 496 { 497 acpi_status status; 498 499 500 status = is_memory_device(handle); 501 if (ACPI_FAILURE(status)) 502 return AE_OK; /* continue */ 503 504 status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY, 505 acpi_memory_device_notify, NULL); 506 /* continue */ 507 return AE_OK; 508 } 509 510 static acpi_status 511 acpi_memory_deregister_notify_handler(acpi_handle handle, 512 u32 level, void *ctxt, void **retv) 513 { 514 acpi_status status; 515 516 517 status = is_memory_device(handle); 518 if (ACPI_FAILURE(status)) 519 return AE_OK; /* continue */ 520 521 status = acpi_remove_notify_handler(handle, 522 ACPI_SYSTEM_NOTIFY, 523 acpi_memory_device_notify); 524 525 return AE_OK; /* continue */ 526 } 527 528 static int __init acpi_memory_device_init(void) 529 { 530 int result; 531 acpi_status status; 532 533 534 result = acpi_bus_register_driver(&acpi_memory_device_driver); 535 536 if (result < 0) 537 return -ENODEV; 538 539 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 540 ACPI_UINT32_MAX, 541 acpi_memory_register_notify_handler, 542 NULL, NULL); 543 544 if (ACPI_FAILURE(status)) { 545 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 546 acpi_bus_unregister_driver(&acpi_memory_device_driver); 547 return -ENODEV; 548 } 549 550 acpi_hotmem_initialized = 1; 551 return 0; 552 } 553 554 static void __exit acpi_memory_device_exit(void) 555 { 556 acpi_status status; 557 558 559 /* 560 * Adding this to un-install notification handlers for all the device 561 * handles. 562 */ 563 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 564 ACPI_UINT32_MAX, 565 acpi_memory_deregister_notify_handler, 566 NULL, NULL); 567 568 if (ACPI_FAILURE(status)) 569 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed")); 570 571 acpi_bus_unregister_driver(&acpi_memory_device_driver); 572 573 return; 574 } 575 576 module_init(acpi_memory_device_init); 577 module_exit(acpi_memory_device_exit); 578